rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3724/1:b..l (detected by 0, t=10502 jiffies, g=37017, q=54 ncpus=2) task:kworker/u4:7 state:R running task stack:22552 pid:3724 ppid:2 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6558 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870 irqentry_exit+0x53/0x80 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653 RIP: 0010:lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666 Code: 2b 00 74 08 4c 89 f7 e8 8f a6 77 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc900045d78e0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff920008baf28 RCX: 1ffff920008baec8 RDX: dffffc0000000000 RSI: ffffffff8b0c13e0 RDI: ffffffff8b5d5ec0 RBP: ffffc900045d7a28 R08: dffffc0000000000 R09: fffffbfff20e7445 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920008baf24 R13: dffffc0000000000 R14: ffffc900045d7940 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:350 [inline] rcu_read_lock include/linux/rcupdate.h:791 [inline] inet_twsk_purge+0x150/0xa40 net/ipv4/inet_timewait_sock.c:295 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x763/0xb60 net/core/net_namespace.c:604 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: rcu_preempt kthread starved for 10528 jiffies! g37017 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:26048 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6558 schedule+0xbf/0x180 kernel/sched/core.c:6634 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965 rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706 rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 6665 Comm: syz.1.745 Not tainted 6.1.105-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 RIP: 0010:__list_add include/linux/list.h:75 [inline] RIP: 0010:list_add_tail include/linux/list.h:102 [inline] RIP: 0010:send_sigqueue+0x3c3/0x720 kernel/signal.c:2001 Code: 33 48 83 c3 08 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 ec 85 8b 00 4c 89 23 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 <74> 08 4c 89 e7 e8 d3 85 8b 00 48 8b 44 24 08 49 89 04 24 eb 0f e8 RSP: 0018:ffffc900001e0c20 EFLAGS: 00000046 RAX: 1ffff1100272336f RBX: ffff888053d225b8 RCX: ffff88807d521dc0 RDX: 0000000000010000 RSI: ffff888013919b78 RDI: ffff888053d225b0 RBP: ffffc900001e0ce8 R08: ffffffff815694ab R09: ffffffff8156a25c R10: 0000000000000002 R11: ffff88807d521dc0 R12: ffff888013919b78 R13: dffffc0000000000 R14: ffff888013919b78 R15: ffff888077441dc0 FS: 00007f6707e136c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000002006b000 CR3: 0000000062380000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: posix_timer_event kernel/time/posix-timers.c:354 [inline] posix_timer_fn+0x186/0x390 kernel/time/posix-timers.c:380 __run_hrtimer kernel/time/hrtimer.c:1686 [inline] __hrtimer_run_queues+0x5e5/0xe50 kernel/time/hrtimer.c:1750 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1812 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1095 [inline] __sysvec_apic_timer_interrupt+0x156/0x580 arch/x86/kernel/apic/apic.c:1112 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202 Code: d1 9d f5 ff 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 0e eb ba f6 48 89 df e8 76 28 bc f6 e8 41 b5 e1 f6 fb bf 01 00 00 00 f6 b8 ae f6 65 8b 05 97 c1 52 75 85 c0 74 02 5b c3 e8 44 e5 50 RSP: 0018:ffffc90004617b30 EFLAGS: 00000286 RAX: 0676305708aed700 RBX: ffff888021262e40 RCX: ffffffff91f32103 RDX: dffffc0000000000 RSI: ffffffff8b0c0260 RDI: 0000000000000001 RBP: ffffc90004617c70 R08: dffffc0000000000 R09: ffffed100424c5c9 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff1100424c65b R13: 000000001c000004 R14: 0000000000000021 R15: ffff8880212632d8 spin_unlock_irq include/linux/spinlock.h:401 [inline] get_signal+0x154b/0x17d0 kernel/signal.c:2873 arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f6706f79e77 Code: ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 <0f> 05 48 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 RSP: 002b:00007f6707e13038 EFLAGS: 00000246 RAX: 00000000000000ca RBX: 00007f6707115f80 RCX: 00007f6706f79e79 RDX: 0000000000000000 RSI: 0000800000000006 RDI: 0000000020001300 RBP: 00007f6706fe7916 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f6707115f80 R15: 00007ffc7dfea318